FIELD OF THE INVENTION
The invention relates to an integrated circuit including a voltage regulator for generating an internal supply voltage, the voltage regulator has one input for applying an actual value and one input for applying a reference voltage as a desired value, the actual value is generated from the internal supply voltage by a voltage divider, and a sensitivity of the voltage regulator is dependent on a resistance of at least one resistor element of the voltage divider.
A voltage regulator of that type is described in a book entitled: Halbleiterschaltungstechnik [Semiconductor Circuitry], 10th edition, Berlin 1993, Chapter 18.3.3, by U. Tietze and Ch. Schenk. An operational amplifier is employed as the voltage regulator to which the actual and desired values are applied. The operational amplifier is followed by a switching transistor that furnishes the voltage which is to be regulated and is derived from a higher voltage, at the output of the regulator. A voltage divider ratio of the voltage divider and the value of the reference voltage determine the value of the regulated output voltage. A leakage current, which flows through the voltage divider disposed between the regulated output voltage and ground, becomes greater as the total resistance of the voltage divider becomes lower. However, if the ohmic resistance of the resistor elements of the voltage divider is increased, then the sensitivity of the voltage regulator is reduced. That sensitivity in fact depends on an RC constant, which is determined by the voltage divider and an associated input capacitance of the operational amplifier.